Fixed it, *whew*! Ended up being a combination bad ignition coil and distributor despite both parts passing all the tests I threw at them. Spark was yellow rather than white, and dist points under the cap were eroded a bit. I'll keep the original text in this post so people can see where I started with it. Thanks for everyone's help and suggestions!

Car just didn't turn over one day. I had probably driven it a week or less before with no problems or odd sounds ,etc.

Car has: half a tank of gas. Has spark. It is definitely pumping gas. Has air flow. Battery has a charge. All the fuses under the hood are good. Starter seems good because it's cranking.

Car sounds like it's juuuust about to start, even sputters a bit on some attempts.

I have sprayed starter fluid in the air intake, so even if fuel pressure was low, it should have started, right? Also took plugs out to let gas evaporate so it doesn't get flooded before trying again. I have smacked the starter motor with a stick (really), though the engine is cranking so it shouldn't be bad.

Didn't see any check engine light, but will check codes on the computer later.

I'm out of ideas here. With all the elements in place, what could keep it from that little bit that gets it to turn over? A sensor? Cracked manifold or gasket? Bad wire? Any ideas?

Make sure your distributor is on tight, Plugs are gaped to specs, ground under distributor, right plugs to right cylinders, check coil, fuel lines backwards? vacuum lines leak free. check ICM and IAVC. Lines hooked up to the rails correctly. could be bad fuel pump. make sure distributor isnt 180 off. If all that dont work it could be your timing.

if you have a "crank no start" and you didn't do any work to it, it just happened than you need to:
1: pay attention and see if it sounds like normal cranking speed
.... If you suspect slower cranking speed hook up battery charger or jump start then crank.... follow lower
.....if you suspect faster cranking speed well lets no go there!
.....if you suspect flooding mash the petal to wot and crank ...This shuts off injectors and airs out engine :Note only crank starter 10 seconds at a time and wait about 30seconds in between cranks so you don't kill your starter
....if you suspect lack of fuel or bad fuel spray starting fluid in throttle body without wizzle stick so it atomizes nicely and crank light to no throttle

What would I do given all your info is correct and you didn't work on it, I would check all the basics of coarse like fluids and suspect fuel quality, maybe take a sample and volume test and or suspect flooding, one thought check coolant temp sensor but should throw fault

The cranking sounds normal to me... The tachometer needle even jumps a bit. I would need a more trained ear listening to it maybe. Good tips on trying to start it though, I'll try in a minute.

New development: the spark plugs spark color seems to more yellow than blue, which apparently is not what it's supposed to look like. I checked my ignition coil with a ohmmeter and the primary resistance read a flat zero, while the secondary resistance was within range. So, I got a new ignition coil and before installing it I tested it and the results are identical: good secondary resistance, but no reading on primary resistance (holding leads on the negative and positive pegs were the plug goes)...?!

I ran my hands around vacuum hoses I think, though having a Silvia hood I don't have that little map. The IAVC should be good since I cleaned it not too long ago. Gas is definitely getting in there, starter spray didn't help, all the plug wires and plugs are working, the distributor and coil are sparking, starter's trying to start.

What I'm hoping for is that it's still an electrical problem causing a weak spark, so I'll continue checking those things, though when a brand new ignition coil gives the same bad reading, I'm afraid I won't be able to correctly diagnose anything I find. :/

EDIT: Can't find info on checking the ohms resistance for the distributor. Is it in the FSM? What other components should I test with the ohm meter that might be causing the yellow spark?

Have you checked your injector connections, some get loose or leak causing starting problems.

Ok, I installed the new ignition coil and now the spark color is bright white. And the car actually started for a second, but when I let off the key thinking it had started, the engine died right away. It seems to be a little closer to starting, but obviously the ignition coil wasn't the main problem.

And no, I haven't checked injector connections yet, but I will now! Also, is there an electrical component to those that might need to be checked?

ViolatoR wrote:Ok, I installed the new ignition coil and now the spark color is bright white. And the car actually started for a second, but when I let off the key thinking it had started, the engine died right away. It seems to be a little closer to starting, but obviously the ignition coil wasn't the main problem.

And no, I haven't checked injector connections yet, but I will now! Also, is there an electrical component to those that might need to be checked?

I just simply wiggle the harness connector which is attached directly to the head of the injector.Might as well check for corrosion as well by simply disconnecting each connector of each injector.

Now I own a 89 240sx and I'm posting pics from that year manual but I'm hoping it'll help...
follow the instructions and if no good check the fuse...


this is for the fuel pump relay and the actual injector,don't go on removing injectors for clogging yet, that's a couple of extra steps and buying OEM injector insulators or rings as well!Just do the electrical stuff!!!

and that's pretty much what I did to mine and found one bad injector with corrosion....Good luck!

Cool, thanks! Ok, so all the injectors look good, no corrosion. Two have been replaced a few years ago, and the car started and ran (very poorly) before they were replaced, so I don't think it's the same problem as back then.

All the injectors give the same voltage reading. And for the resistance test they all gave a continuity reading (I'm guessing that's what it's called) where they close the circuit and zero the ohmmeter, though they didn't give the suggested result of 10-15ohms. I'm thinking that like when I tested the primary resistance on both the old and new ignition coil, a zero reading at least means there's a working circuit, but I don't know why these things aren't giving the suggested ohm reading (?). I only have one ohm setting on my meter, maybe that's a limitation.

The fuel pump relay gives a continuity reading, but no voltage reading between terminals 3 & 4, though my meter doesn't have a 12v DC setting only a 10, 50, 250 and 500, so maybe another meter would read it correctly. Then again, there's clearly fuel being sprayed on the spark plugs; would they spray if the relay was not working?

I'm starting to think I should check the timing and get it over with, because all the other pieces of the puzzle seem to be there.

Opened valve cover today. Camshafts are correctly oriented with pulley at Top Dead Center, and the distributor is at the first point. where it should be, and the timing chain is tight, and there's no indication of anything going wrong under there. The only problem is that when I got my fuel injectors replaced the shop way over torqued the bolts holding it down and filled the threads of some of the bolts with stripped aluminum! D:< None of the little aluminum fragments got into the engine though, but I don't know if I can even get the valve cover back on with a perfect seal. Anyways, timing doesn't appear to be an issue here.

First, so you don't have to read it all, I have: charged battery, half a tank of gas, oil, good fuses, and at the engine: spark, fuel and air. Timing looks good from what I can tell (see above). I re-checked as many hoses and ground wires and random thingies I could, and didn't see anything that looked torn or disconnected. Car ran fine one day and didn't start the next.

So I rented a compression gauge from Autozone today. I only cranked the engine 5 times (the article on this site says 7, but I didn't read that first) and got a reading of 250-300kpa across the board. The article says it should be about 1,000-1,200kpa. Of course on a thread I found here, someone said you can't get a correct reading without warming the engine up anways. And other people seem to think it should start with even lower readings: someone said that only 100kpa is needed to get the gas to combust. Long story short, I have at least some compression, even with a cold engine, and the car has semi-started a couple times but won't stay on.

Now I'm going to bite the bullet and tow it to a shop and have the guy tell me I need new muffler bearings or blinker fluid and all my problems will be solved, for a nominal fee that is.

you got low compression due to the fuel flood. should have taken all the plugs out dried the engine by cranking with fuel pump off, put some trany fluid in each cyl (like a table spoon in each) recheck ur compression if ok, check ur fuel pressure with a gauge make sure is up to spec, check spark at the end of the wires with new coil spark should jump 30 thounds no problem reassemble everything

Have you checked the MAF. Try swapping one in that you know is good, like from a buddies whip. Sounds like a bad MAF to me.

check ur air gap on your distributor cap, if the bushings are worn, u can put a little bit of solder on them to make sure if thats the problem or not before you buy another cap

MAF is good. Interesting about the Dist points and the air gap, didn't know about that, but the points are a little deteriorated. I think I might just get a new cap then. No solder to test, and man do I suck with a soldering iron! I'll let you know if it helps. This is the craziest car problem I've had. Maybe once it's solved, the fix will be like penicillin for car problems!

didnt i say check for spark at the end of the wires where the wire goes in to the spark plug?????

Does the check engine light come on with Key on-Engine off? It should. I had a problem a couple of weeks ago with my car stalling without giving it gas, I cleaned up the ground going from the head to the chassis (chassis side was a little rusted) and added a ground from the chassis to the battery negative, car idled like a champ. Just something to try.

qwertyz wrote:didnt i say check for spark at the end of the wires where the wire goes in to the spark plug?????

Yes, thank you for your advice. Was a nice spark. Cleared fuel from the engine. Installed new distributor cap today, and combined with the new ignition coil, the engine sounded better and better.

So, it's running now, though it was about to die when it started so I gave it a little gas. Maybe that's because I had cleared the lines by cranking it with the fuel pump off. I'll let it run for a bit then turn it off and try again.

Thanks again to everyone for their advice and help. I really learned a lot about troubleshooting this car!

Edit: Ok, let it ran for a bit and turned it off and it started back up just like new. *Whew*! So, bad spark from ignition coil and deteriorated distributor cap points appear to be the main culprits here. The dist points were eroded away a little bit, so I guess when I came home one day, one of the points dissolved a little too much so it didn't start the next day. Anyways, let that be a lesson to anyone who hasn't checked under their distributor cap recently!

not checking spark color and distributor points gets almost everybody. its always the simple s*** lol. good job man

good job mate i am glad it worked out